Lo Loestrin FE

"Oct. 18, 2012 -- While the use of long-acting intrauterine devices (IUDs) is increasing, 1 in 9 women at risk for unintended pregnancies is not using any birth control, according to a new government report.

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to the rates in the clinical trials of another drug and may not reflect the rates observed in practice.

A multicenter phase 3 clinical trial evaluated the safety and efficacy of Lo
Loestrin Fe for pregnancy prevention. The study was a one year, open-label,
single-arm, uncontrolled study. A total of 1,660 women aged 18 to 45 were enrolled
and took at least one dose of Lo Loestrin Fe. [See Clinical Studies.]

DRUG INTERACTIONS

Changes in Contraceptive Effectiveness Associated with Co-Administration
of Other Products

If a woman on hormonal contraceptives takes a drug or herbal product that induces enzymes, including CYP3A4, that metabolize contraceptive hormones, counsel her to use additional contraception or a different method of contraception. Drugs or herbal products that induce such enzymes may decrease the plasma concentrations of contraceptive hormones, and may decrease the effectiveness of hormonal contraceptives or increase breakthrough bleeding. Some drugs or herbal products that may decrease the effectiveness of hormonal contraceptives include:

barbiturates

bosentan

carbamazepine

felbamate

griseofulvin

oxcarbazepine

phenytoin

rifampin

St. John's wort

topiramate

HIV protease inhibitors and non-nucleoside reverse transcriptase inhibitors:
Significant changes (increase or decrease) in the plasma levels of the estrogen
and progestin have been noted in some cases of co-administration of HIV protease
inhibitors or of non-nucleoside reverse transcriptase inhibitors.

Antibiotics: There have been reports of pregnancy while taking hormonal
contraceptives and antibiotics, but clinical pharmacokinetic studies have not
shown consistent effects of antibiotics on plasma concentrations of synthetic
steroids.

Consult the labeling of all concurrently-used drugs to obtain further information about interactions with hormonal contraceptives or the potential for enzyme alterations.

Changes in Plasma Levels of Co-Administered Drugs

COCs containing some synthetic estrogens (e.g., ethinyl estradiol) may inhibit the metabolism of other compounds. COCs have been shown to significantly decrease plasma concentrations of lamotrigine, likely due to induction of lamotrigine glucuronidation. This may reduce seizure control; therefore, dosage adjustments of lamotrigine may be necessary. Consult the labeling of the concurrently-used drug to obtain further information about interactions with COCs or the potential for enzyme alterations.